I do not think changing hosts file is a good idea.

IMHO, the best solution at present is a graceful error notice appearing when checking connectivity hang there after some time. That notice should guide user to change the url in `key-value "connectionCheckUrl": "http://www.google.com/" in $JENKINS_HOME/updates/default.json `

That advice would have very limited geographical relevance, as google.com was specifically chosen because of it's solid availability. In most countries, if google.com isn't available, nothing else is either.

That said, maybe something like Microsoft's http://www.msftncsi.com/ncsi.txt would be a better choice. Can you connect to that site?

JENKINS-15124 notes that some shit proxies return nice looking error pages instead of error responses, so having a reference URL with defined content that can be compared would be nice.

Please answer the question in the comment from Oct 11 if you're still interested in a solution to this.

If the need in the end is that it is possible to reach the update site, then why bother checking www.google.com, why not check that you can reach the update site?

It is possible to rsync the update site and update the update site URL in Jenkins, so it appears to be a valid use case to have an internal update site anyway. In that case this internet issue is artificial and should be able to be avoided if desired as a configuration option within the update management IMO.

Any update on this problem?

I can ping updates.jenkins-ci.org and download package manually but cannot use the update center.

I guess the problem is because the server is behind GFW. But why bother test against other site when you want to connect to THE SITE if I follow the comments correctly.

If you want to update some plugins, you can modify jenkins_home/updates/default.json ,change connectionCheckUrl from http://www.google.com/ to some one you can access ,maybe https://www.baidu.com for china, then reload configuration,and install plugins.But jenkins will get this file daily,so if you need,you can do it.

pipehappy

danielbeck: What do you think?

Could we just set http://updates.jenkins-ci.org/ as the connectivity check URL in the JSON? It is reliable, and is what the code currently checks anyway at the moment (after checking Google):
https://github.com/jenkinsci/jenkins/blob/jenkins-1.647/core/src/main/java/hudson/model/UpdateCenter.java#L1062

If you can't reach the Jenkins update server, then you have problems anyway. In the worst case, if that host really is down, then the user would be informed, and asked if they need to make proxy changes. But that should be rare, and the same would happen anyway for people in countries where Google can end up being blocked.

Just wondering, as somebody was asking about the connection check URL here:
https://github.com/jenkinsci/backend-update-center2/pull/40#issuecomment-183517346

I have no idea if this helps at all, but seganw you might be to hit our mirrors directly for your update-center.json.

A list of the mirrors can be found here and from each mirror listed you should be able to navigate to updates/ and then select either the latest update-center.json or the LTS version (stable/update-center.json)